I replaced my thermostat back when I got the car around February. Since then its been fine up until a few days ago. I had a check engine light on for about 2 months because of a CTS. It took me a while to get to it because everything was running fine so I just let it be until I had the time. About 2 days after I replaced the CTS I noticed my car was not getting up to operating temp. It only makes it to the mark right before the middle and sometimes only the first mark. When I replaced the CTS I did lose some coolant and I have not yet got the chance to fill it back up to the full line. Im wondering if the lower amount of coolant is causing the improper heating or did the bad CTS cause my thermostat to go bad also? Seems odd a new thermostat would only last a few months. To me it seems like it has to be the thermostat. Anyone got anything else or should I replace the thermostat?

 

I can't imagine how it could possibly be the CTS (unless it's defective) and there's no way a lack of coolant could cause that.

If our thermostats do in fact get stuck open when they go bad; then I'd start there.

 

I know it's not the CTS now. I was just wondering if leaving a bad CTS in for so long caused the thermostat to go bad as well.

I guess I will replace the thermostat again, cheap part to replace. The coolant @ $30 is more than the thermostat.

 

If your old coolant looks okay, you can re-use it IMO. Just use some sort of a clean rag in a funnel that is stuck in the coolant reservoir, and pour in the used coolant so that the rag filters out any particles from the coolant.
I use a normal paper towel as the rag.

 

Yeah that's true. Wasn't thinking.

 

New thermostat ordered

 

Here in Australia, a genuine thermostat from Audi is $92!

 

I'm sure here in the US it is too. But I would never buy direct from the dealer. Paid under $15 for the one that should be here Friday.

 

Genuine?

 

Yes OEM from eBay.